ASME PTB-3 Validation – Fatigue Analysis

Equipments when subjected to cyclic loads may fail due to fatigue. As an illustration consider an example of a wire being bent back and forth until the plastic deformations grow so that it ruptures. In ASME fatigue analysis typically the cyclic loads are pressure and/or temperature. Here an ASME PTB-3 Validation for “Example E5.5.3 – Elastic Stress Read more about ASME PTB-3 Validation – Fatigue Analysis[…]

ASME PTB-3 Validation – Buckling Analysis

Linear/Eigenvalue Buckling analysis are fairly easy to set up and post process. Typically an Eigenvalue Buckling Analysis is preceded by a static structural analysis with perturbation load leading to compressive stress field being generated in the model. The pre-stressed model from the static structural analysis is then analyzed for buckling failure modes. Results of buckling Read more about ASME PTB-3 Validation – Buckling Analysis[…]

ASME PTB-3 Validation – Protection Against Local Failure

In addition to demonstrating protection against plastic collapse, the analyzed components must also qualify the local failure check per section 5.3 of ASME Sec VIII Div 2. The code gives two analysis methodologies to do this.The first method is to carry out an elastic analysis and check triaxial stress limit given as 4S by eq Read more about ASME PTB-3 Validation – Protection Against Local Failure[…]

ASME PTB-3 Validation – Elastic Plastic Analysis

Elastic Plastic Analysis is a non-linear analysis. There are two main non-linearities involved here. The material model is non-linear and requires true stress strain curve as input. In contrast a linear static analysis just needs Elastic Young’s Modulus to construct the full stress strain curve. The stress-strain curve in this case is simply a line Read more about ASME PTB-3 Validation – Elastic Plastic Analysis[…]

ASME PTB-3 Validation – Limit Load Analysis

Limit Load analysis are non linear in nature and may require significantly more computation time and resource than a linear elastic analysis. As such a linear elastic analysis is always a recommended first step. It helps to ensure the FEA problem is correctly setup i.e. there are no rigid body motions, deformations and far field Read more about ASME PTB-3 Validation – Limit Load Analysis[…]

ASME PTB-3 Validation – Elastic Stress Analysis

I carried out ASME PTB-3 Validation for “Example E5.2.1 – Elastic Stress Analysis” to check for protection against plastic collapse per ASME Sec VIII Div 2 using ANSYS. Here’s a summary. Problem Statement: Evaluate the vessel top head and shell region for compliance with respect to the elastic stress analysis criteria for plastic collapse provided Read more about ASME PTB-3 Validation – Elastic Stress Analysis[…]